The present invention relates to an improved collator for crimping a plurality of continuous sheets into continuous multiple copy forms and more particularly, to a modular collating assembly having a freely rotatable platen.
Typically, continuous multiple copy forms are assembled from separate sheets having holes along both margins which are spaced so as to be compatible with standard pin drive equipment. For example, most computer printers have pin drives designed to accept paper with hole centers spaced one-half inch apart along both edges. In the use of such multiple copy forms it is essential that the holes of each forms layer be maintained in substantial alignment so as to properly engage the respective pin drives of printers or other equipment connected with multiple copy forms manufacture and use. A preferred method of securing the multiple copies of such forms in proper alignment is to provide a series of crimps to the edges of the multiple sheets while the sheets are held in alignment with each other. Each crimp serves to hold the multiple sheets together by displacing small segments of the sheets so as to form a sufficient entanglement of the displaced but unsevered segments to connect the sheets at the crimp site.
One problem which occurs when collating multiple copy forms is that the multiple separate sheets of continuous paper which make up the multiple copy forms are not always uniform themselves. This problem is especially prevalent in multiple copy carbonless forms because the various chemical treatments to which the various separate sheets are subjected may shrink or otherwise distort one sheet out of conformity with the others. When the separate sheets are crimped together into a multiple copy forms, this non-uniformity can cause stresses, even "bubbles", within the crimped multiple copy forms leading to subsequent problems when driving, folding or printing such forms.
Continuous multiple copy forms collators of the prior art, such as Smith, U.S. Pat. No. 3,475,249, Whitesell, U.S. Pat. No. 3,727,908, Gaspar, U.S. Pat. No. 4,536,176 and Richey U.S. Pat. No. 4,601,693, all use some type of pin drive having a plurality of pins to move the continuous multiple sheets through the collating machine and to maintain the sheets in alignment between a rotating crimping blade and an opposed driven platen. In all these devices it is necessary that the moving crimping blade, moving multiple sheets and moving platen surface all come into simultaneous engagement while moving at an identical linear speed so as to achieve the desired crimp pattern and to prevent misregistration or tearing of the multiple sheets. As discussed in Richey, variations of hole spacing and other irregularities in the paper inevitably occur, often resulting in a bubbling effect between the layers of the multiple copy form. This condition can cause misalignment of the sheets at the crimping site thereby resulting in permanent misalignment of the final multiple forms.
To achieve proper alignment at the crimping site, Richey employs a rotating cylindrical crimp blade holder having a plurality of pins about its circumference interspaced with a plurality of crimp blades. Thus, the crimp blade holder serves as both crimping element and pin drive element. To achieve proper alignment of the multiple sheets at the moment of crimping, Richey uses a pin forward of the crimp blade in the direction of rotation to align the sheets immediately prior to crimping, and another pin, rearward of the crimp blade to maintain alignment as the crimp blade exits the paper. (See Richey, FIGS. 9 and 10) Richey's crimp blade holder is used in cooperation with a driven cylindrical platen having annular grooves for receiving the crimp blades and having a plurality of holes for engagement with the pins. The multiple sheets pass between the two cylindrical bodies at the proper linear speed and with selected paper holes engaged in sequence by the pins.
Unfortunately, the devices described above present several disadvantages. Foremost among these disadvantages is the relatively complicated system of gears and shafts which are required to achieve an identical linear speed for the pin drive, platen, and crimp blade. Further, in Richey for example, it is necessary to disengage the crimp blade holder cylinder from the platen in order to thread new sheets, or to service damaged blades or pins. Finally, when inadvertent misalignment or misregistration between the driven crimp blade holder cylinder and the driven platen does occur, the pins may be broken off or other serious damage could be inflicted upon the apparatus.